Cambodian authorities have arrested two leading figures from the notorious 1970s Khmer Rouge regime and charged them with crimes against humanity.

Former Foreign Minister Ieng Sary and his wife, Ieng Thirith, were taken into custody in the capital, Phnom Penh.

The pair, who deny any wrongdoing, are due to appear at a UN-backed genocide tribunal on Wednesday.

The brutal Maoist regime, which ruled between 1975 and 1979, is blamed for more than one million deaths.

A tribunal was established last year to bring surviving leaders to the dock.

"Today Ieng Sary and Ieng Thirith have been arrested in execution of an arrest warrant... for crimes against humanity and war crimes as regards Ieng Sary and for crimes against humanity concerning Ieng Thirith," a statement from the tribunal said.

Purge of intellectuals

Police surrounded the couple's Phnom Penh house early in the morning.

WHO WERE THE KHMER ROUGE?

Maoist regime that ruled Cambodia from 1975-1979

Founded and led by Pol Pot, who died in 1998

Abolished religion, schools and currency in a bid to create agrarian utopia

Brutal regime that did not tolerate dissent

More than a million people thought to have died from starvation, overwork or execution